Two-stroke cycle internal-combustion engines have been used for decades as power plants in automobiles, trucks, motor boats, motorcycles, lawn mowers, snow removers, power saws and other similar equipment. Since they are usually air-cooled and do not require a camshaft and valve trains, they are relatively lightweight, simple in construction and easy to service. Therefore, two-stroke cycle engines are desirable to run equipment that must be handled and moved around. However, because of problems, such as too much exhaust pollution, poor power output at low speeds and lower fuel efficiency in comparison with four-stroke engines, two-stroke cycle engines generally have not been used in automobiles during the last two decades.
In order to eliminate the disadvantages associated with two-stroke cycle engines and enable their use in automobiles, significant improvements have recently been made in the development of the two-stroke engine. Two of the most important improvements in the prior art are Ralph Sarich's engine developed by Orbital Walbro in Australia and the stepped piston engine developed by Bernard Hooper Engineering (BHE) in the United Kingdom. Both of these engines seem to provide the possibility of eliminating the disadvantages of the classical two-stroke engine and enabling significant savings with regard to the engine's manufacturing costs, size and weight. However, Orbital's engine requires sophisticated additional equipment in order to satisfy the requirements and BHE's engine requires at least two cylinders in order to function and can be manufactured with an even number of cylinders. It is not likely that these engines will be used as power plants for low cost simple equipment, either because of their manufacturing costs or inability to function as a simple single-cylinder engine. Indeed, the object of these inventions was to provide a two-stroke engine for use in automobiles and boats.